JPH02199166A - Thermoplastic polyurethane molded item and preparation thereof - Google Patents

Abstract

PURPOSE:To obtain the title molded item with excellent blocking property by incorporating specified amt. of each specified mica powder and higher fatty acid amide in a thermoplastic polyurethane molded item. CONSTITUTION:A thermoplastic polyurethane resin compsn. contg. 1-35wt.% mica powder with pref. a wt.-average flake diameter of 3-100mum and the max. diameter of 150mum or smaller and 0.5-5.0wt.% higher fatty acid amide (e.g. stearamide) is melt-extruded to obtain the title molded item contg. the specified amt. of mica and higher fatty acid amid.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a thermoplastic polyurethane molded product with good blocking resistance, and can be used for various purposes as a flexible and stretchable film, sheet, or hose. .

(Prior Art) The technology of melt-extruding thermoplastic polyurethane and processing it into films, sheets, or hoses has been slow to progress compared to other thermoplastics due to the adhesiveness (blocking properties) of the resin.

Recently, compared to rubber that exhibits the same type of elastic behavior, strength,
The development of thermoplastic polyurethane films, sheets, and hoses has been in the spotlight as their good abrasion resistance has been recognized.

(Problems to be Solved by the Invention) However, conventional films, sheets or hoses made of thermoplastic polyurethane have problems in selecting and using an effective anti-blocking agent to improve blocking resistance, and are not stable on the market. It has not reached the level of supply. Moreover, the reality is that expensive additives have to be used for molding.

An object of the present invention is to make it possible to stably implement the lack of improvement in blocking resistance in the past at low cost.

(Means for Solving the Problem) The present inventors have prepared mica powder having a weight average flake diameter of 3 to 100 μm and a maximum diameter of 150 μm or less.
5% by weight and 0.5-5.0% by weight of higher fatty acid amide.
Containing thermoplastic polyurethane film sheet or hose (
It has been found that a molded product (hereinafter sometimes referred to collectively as a molded product) achieves the above object.

The present invention is characterized in that mica powder of a specific particle size and higher fatty acid amide are added together in specific amounts to a thermoplastic polyurethane resin, and then molded.

Examples of the thermoplastic polyurethane resin used in the present invention include high molecular polyols such as polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, polyethylene adipate, polypropylene adipate, polybutylene adipate, and polycaprolactone, and 4,4-diphenylmethane diisocyanate. , 1,5-naphthalene noisocyanate, 2,4-tolylene diisocyanate, hexamethylene diisocyanate and other organic isocyanates with ethylene glycol,
Examples include, but are not limited to, extrudable thermoplastic polyurethane resins prepared by reaction with chain extenders such as 1,4-butanediol;
Any type of thermoplastic polyurethane resin can be used as long as it has a molecular weight that allows melt molding.

The type of mica powder used in the present invention is not particularly limited, and is appropriately selected from muscovite (muscovite), phlogovite, sericite, biotite, soda mica, synthetic mica, etc. can do.

When talking about the particle size of mica powder, mica has a flat shape, as is well known, and the "weight average flake diameter j
It is appropriate to express it using the following parameter. The average flake diameter (g) is calculated by classifying the powder using microsieves or sieves with various openings, and using the results as Ro@in-Ra.
The opening Q of the microsieve or sieve is plotted on the AALAR diagram and allows 5 oit m% of the total weight of the powder subjected to measurement to pass through. It is determined by the following O)2 or formula (2).

Q ” ff5e (for microsieve) (
1) e = si'"Qsa () Rui
(2) Here, the part of the 7x mother powder that has a large particle size with a weight average diameter of about 40 μm or more is classified by a sieve, and the fine part with a weight average diameter of about 40 gm or less The parts are classified using a microsieve.

According to the study results of the present invention, flakes with a weight average diameter of less than 3 μm have poor ability to form irregularities on the surface of the molded product.
Poor effectiveness as an antiblocking agent. In addition, the bulk specific gravity of the particles becomes small, and a large volume of particles must be added, making uniform mixing difficult. Furthermore, the cost also increases. On the other hand, when the weight average flake diameter exceeds 10 Gμm, the surface of the molded product is so uneven that it feels rough to the touch, and only a low-quality product can be obtained. Furthermore, if the maximum diameter of the powder exceeds 1 sOus, holes may form in the formed film, reducing the commercial value. For the above reasons, the weight average flake diameter of mica is suitably in the range of 3 to 100 μl, more preferably in the range of 5 to 75 μm. Also, the maximum diameter is 1
It is 50 μm or less.

The particle size of mica changes in the direction of decreasing during the molding process due to kneading in an extruder, etc. The particle size indicated in the present invention means the particle size of mica obtained by burning and recovering a molded body in an electric furnace.

There is no particular restriction on the weight average aspect ratio of the mica powder used in the present invention, but it is generally preferably 10 or more. It is thought that the flat surfaces of the mica are oriented to some extent parallel to the surface of the molded product, thereby achieving the anti-blocking effect while maintaining strength.

The amount of mica to be added is determined taking into consideration both the anti-blocking effect and the physical properties of the molded article. If the amount added is small, the anti-blocking effect will be poor, while if the amount added is large, the strength, elongation, and tear strength of the molded article will be significantly reduced. A more preferable addition amount is 2 to 25% by weight. Considering that the amount of a slip agent added to improve blocking resistance is generally on the order of pp-, it is a feature of the present invention that the amount of mica added is large.

The higher fatty acid amide used in the present invention can be appropriately selected from stearic acid amide, oleic acid amide, methylol stearamide, ethylene bis stearamide, methylene bis stearamide, etc.
Ethylene bisstearamide is particularly effective. These higher fatty acid amides are a type of lubricant for plastics, and other lubricants include metal soaps, aliphatic hydrocarbons,
There are alcohols, higher aliphatic types, etc., and more specifically, zinc stearate, calcium stearate, polyethylene wax, montan acid wax, etc. are used.

However, according to the present invention, among the lubricants for plastics, only by using higher fatty acid amide together with mica,
A thermoplastic polyurethane molded article with good blocking resistance can be obtained.

Addition of mica alone has a considerable effect on improving blocking resistance, but with smaller average particle diameters, such as muscovite 300G, without a lubricant, blocking resistance may not be sufficient unless a large amount of mica is added. However, by using higher fatty acid amide in combination, even if the amount of mica added is small, the blocking resistance is improved and a good molded product can be obtained without deterioration of mechanical properties.

In the present invention, the thermoplastic polyurethane composition containing mica and higher fatty acid amide can be produced, for example, by the following method.

The raw material, which is a mixture of thermoplastic polyurethane resin pellets, mica, and higher fatty acid amide, is introduced into the hopper of a melt extrusion molding machine, kneaded in the extruder, and the strands melted and extruded from the strand die are cut with a cuffer. Obtain a beret of the desired composition. In order to achieve good kneading properties, a two-wheel screw type extruder is preferable to a single screw type. Mica and a third component other than mica are supplied separately from the thermoplastic polyurethane from another feeder, and the extruder is A mixing method is also possible.Furthermore, in some cases, it is possible to omit the above pelletizing operation by adding mica and higher fatty acid amide during thermoplastic polyurethane polymerization.

The method of molding a molded article from a thermoplastic polyurethane composition containing mica, etc. is not particularly limited, but an inflation molding method in which a pellet made of the composition is melt-extruded in an extrusion manner and then molded into a cylindrical film through a ring die is widely used. There is. A sheet forming method in which the material is solidified on a cast roll through a T-die, and a hose forming method in which the material is formed through a ring die and a siling device can also be used.

Next, we will explain "blocking resistance", which is an important term among the terms used in the present invention. Blocking refers to the phenomenon of adhesion to nip rolls and casting rolls and failure to separate when forming a film or sheet. Therefore, it is simple and effective to use the degree of adhesion to the roll during molding as a measure of good or bad blocking resistance.The surface of the mating roll is generally finished with chrome plating. And that's what I used.

On the other hand, in film forming processes such as inflation molding, in which cylindrical bubbles are formed and the bubbles are nipped and folded, the blocking ability of the films together becomes an issue. ° was used.

Hereinafter, the present invention will be explained in more detail with reference to Examples. Note that the measured values in the examples were determined according to the method shown below.

Slip angle: Using a friction mesh measuring machine manufactured by Toyo Seiki Co., Ltd., width 30-1, length 4o--, height IQam, weight 1-9
This is the value measured at 20°C at the angle at which a test piece made of a 2g weight wrapped in a molded film begins to slide on a plate covered with the same film.

Roll Adhesiveness Confirmed by the adhesion of the film to a nichrome plated roll.

Strength, elongation, and tear strength are values measured using an Instron tensile tester.

Next, the present invention will be explained by examples.

XjiliN l Thermoplastic polyurethane resin (Product name: Kuramiron@U 1
190), 5 wt.
and Nirasan Alflow) 150T (manufactured by NOF) 1
．． While adding 0% by weight, pellets were obtained by melt-kneading using a TEX-30 two-wheeled extruder (manufactured in Japan) (extrusion temperature = 175-205°C, discharge amount + 8kg/
H, screw rotation speed: 160 rpm). The MFI value (19[
1"c') was 3.5 g/10 minutes.

The pellets were vacuum dried at 80°C for 6 hours and the moisture content:
200ppm), die diameter 40φ, slit interval 1.
It was molded into a film using a 0-1 isofresion molding machine (manufactured by Placo) at a discharge rate of 6 kg/hr.

Stable molding was possible with no problems with either the tackiness on the upper nip roll or the blocking property on the winding machine. Table 1 shows the quality and physical properties of the obtained film.

Example 2 Thermoplastic polyurethane resin (trade name: Clamiron@U
119G), weight average flake diameter 18μ, maximum diameter 60
μ fan's white! Pellets were obtained in the same manner as Example 11 while adding 2% by weight of Mother 400W and 3.0% by weight of Nirasan Alflo ■H50T. (Extrusion temperature 170-205℃,
Discharge amount 7kg/H, screw rotation speed 1.5Orpm)
The MPI value of the pellet was 4.0 g/lo min.

The pellets were made into a die with a die width of 200 mm and a slit interval of 1.2 mm.
A polyurethane sheet having a thickness of 150 μm was obtained by discharging it onto a cast roll at 30° C. using a No. 1 T-die.

It had little adhesion to cast rolls and could be stably formed into a sheet.

Example 3 Under the conditions of Example 1, Clamyron@ was used instead of Clamyron@ U 1190 as the thermoplastic polyurethane resin.
U 1195 was used, and the amounts of Muscovite 3000 and the lubricant Nirasan Alflo @ HSOT were 10.0% by weight and 0.
Pellets were obtained under the same conditions as in Example 1 except that the concentration was reduced to 5% by weight. 'A good polyurethane hose could be molded by melt-extruding this pellet through a ring die with a die diameter of 25φ.

Comparative Examples 1 to 4 Under the conditions of Example 11, the type and amount of lubricant added were changed. Comparative example 1) without lubricant, Nirasan Alflo-H50T
Hostalb W E which is Montan acid wax instead of
-4 (manufactured by Hoechgt) (Comparative Example 2), zinc stearate (Comparative Example 3), and polyethylene wax Sunwax 0151P (manufactured by Sanyo Chemical Co., Ltd.) (Comparative Example 4), under each condition. The physical properties of the obtained film are shown in Table 1, and compared to the film obtained in Example 1, it had some defects in blocking properties or film physical properties.

(Effects of the Invention) As explained above, according to the present invention, a molded article made of thermoplastic polyurethane can be produced which retains its original good physical properties and has a significantly improved anti-blocking effect. All three should be provided at a low price.

Patent applicant RiRashi Co., Ltd.

Claims (2)

[Claims] (1) 1 to 35% by weight of mica powder with a weight average flake diameter of 3 to 100 μm and a maximum diameter of 150 μm or less
and a thermoplastic polyurethane molded article containing 0.5 to 5.0% by weight of higher fatty acid amide. (2) The molded article according to claim 1, wherein a thermoplastic polyurethane resin composition containing 1 to 35% by weight of mica powder and 0.5 to 5.0% by weight of higher fatty acid amide is melt-extruded. manufacturing method.